Known already for some time now is a drive system for motor vehicles which, in addition to a conventional combustion engine, also has an electric motor that is integrated into the drive mechanism of the motor vehicle either alternatively or also concurrently. These drive systems, known as “hybrid drives”, have many advantages from the ecological point of view, since the mixed type of drive mechanism can also achieve significant savings in energy in mixed driving (city/country) when compared to an exclusively combustion engine drive.
Such hybrid drives for motor vehicles have been disclosed in DE 199 17 665 A1, which has a first electric motor located within the drive mechanism between the combustion engine and the vehicle drive mechanism and a second electric motor permanently linked to a transmission drive shaft. Additionally, a gearshifting clutch is located between the electric motor and the combustion engine operating as a motor and as a generator.
In practice, the axial construction length of the motor vehicle drive mechanism, especially in the front traverse arrangement, plays a significant role. In order to achieve an especially short drive design, it has been shown to be useful to take advantage of the free construction space within the rotor of the electric machine. In this respect, it is know that at least one coupling of the drive system could be used there whereby, preferably a wet-running or, as the case may be, oil-cooled multiple disk clutch can be inserted.
Nevertheless it has shown to be disadvantageous when an annular gap between the rotor and the stator of an electric motor which, as such should remain free of oil, is used with the above noted cooling oil, since the centrifugal force created radially pushes the oil outward through the disks of the multiple disk clutch and is returned in a large diameter back to the crankcase sump. In the studies completed with such diameters, and based on the usual number of revolutions, or because of the high rate of rotation of the motor vehicle's drive mechanism or, as the case may be, its peripheral velocity affecting the seals, these have not been shown to be useful for the annular gap, since they are subjected to a relatively high rate of wear and tear. Here is where the invention described in the following text enters the picture.
The purpose of the invention is to provide a relatively abrasion-free seal for an electric machine or motor that is inserted within the motor vehicle drive mechanism. A wet-running oil cooled gearshift element, for example, a multiple disk clutch, being accommodated within a free construction space of a rotor of the electric machine with which an annular gap, free of oil to the highest degree possible, between the rotor and the stator of an electric machine is practicable.
According to the invention, this task together is solved in that in order to achieve the highest possible level oil-free annular gap between the rotor and the stator of the electric motor, at least one lining is to be arranged at the front-facing side of the annular gap, which for its part, is designed to seal, at least at high rate of rotation by the rotor, without touching.
According to an advantageous design of the invention, the lining is fashioned in such way and arranged on the rotor so that at a standstill or at a low rate of rotation it seals the annular gap by being in contact and that at a high rate of rotation, it is released from the annular gap.
Furthermore, it is recommended, in the sense of the invention, that the lining be formed through a more or less familiar V-ring.
Additionally, it is foreseen that the annular gap, preferably at the location of the lining that is on the opposite side of the electric machine, be linked to an air intake opening.
Finally, it is recommended that the air intake opening be connected through a vent pipe with the interior of the motor vehicle drive mechanism that is linked to the vehicle transmission.